A 15 percent drop in blood transfusions this year is being blamed for an 18 percent staff reduction at Community Blood Center of the Ozarks. CBCO, which supplies blood products to 38 area hospitals, is laying off 39 employees. 27 full-time and 12 part-time positions are being eliminated. A CBCO spokesman says the layoffs are necessary because of a decline in the number of requests that it gets from hospitals for blood products. Better technology and changes in medical has reduced the need for some transfusions.